There appears to be two mechanisms involved in controlling the respiratory response of an individual when he is engaged in exercise. The first mechanism is a neural mechanism. There are nerve receptors in working tissues which increase their frequency of firing when an individual engages in physical activity. This increase in neurological activities causes an increase in the respiratory effort of the individual in both rate and tidal volume. This neural mechanism works at the moment exercise begins. A second mechanism appears to modify the respiratory response in a slow manner; this is a humoral mechanism. Chemical changes in the blood, to include changes in the oxygen and carbon dioxide content and the hydrogen ion concentration will affect the individual's respiratory response. Many athletes state that one of the greatest difficulties they experience between training and racing is the perception that they can feel their increased respiratory effort, yet are still unable to get sufficient amounts of air.
The anatomical dead space is the quantity of air which can be found in the mouth, throat, trachea, main stem bronchi, and the large bronchioles of the lungs. The gas contained in the anatomical dead space does not participate in the diffusion resulting in blood-born oxygen. Increasing the anatomical dead space over a period of a few minutes creates subtle changes in the blood causing an increased respiratory effort on the part of the athlete. By enlarging the anatomical dead space, the individual's respiratory effort will exceed the respiratory requirement of the particular work load he is using in his training.
An earlier method for increasing the respiratory rate utilized a gas mixture with sub-atmospheric oxygen levels. The user would respire through a scuba-type device connected to a gas cylinder. This method has several disadvantages for use during strenuous exercise. The apparatus is bulky and cumbersome. Also, a supplier of the gas composition would be difficult to locate.
Many of the other devices utilized in improving respiratory effort and response were developed for therapeutic use by victims of respiratory ailments.
In U.S. Pat. No. 3,455,294 (Adler) a device is described for use in the treatment of patients suffering from pneumonia and varying forms of pneumonitis. The object of the Adler device is to increase carbon dioxide inhalation by the patient. This stimulates the individual to breathe deeper. An increase in the tidal volume of the patient often results in effective coughing to clear the lung of bronchial obstruction with mucous. The device itself consists of a series of cup-shaped internal chambers contained within a larger chamber. Such members are positioned to provide a tortuous pathway for respiration. Patients are advised to use the device for 3 to 5 minutes at hourly intervals. The Adler patent also describes means for injecting medicaments into the device to facilitate respiration.
This invention provides several advantages over the prior art. This device is easy to use. Its simplicity makes it more attractive to the user. There are no gas cylinders to attend to, nor suppliers of the right oxygen poor composition to locate. This invention is also more suited to use by athletes in training than the device described in U.S. Pat. No. 3,455,294. The Adler device is not designed for use at higher repiration rates nor during strenuous activity. There are no means provided to clamp the device securely to the mouth. The invention herein disclosed provides a light weight and unobtrusive means to facilitate endurance training. Specifically, this device is worn by endurance athletes during their training sessions to prepare their respiratory mechanism for competition.
It is therefore an object of this invention to force the respiratory system to work and ventilate at a higher rate than that dictated by the actual work or training being done.
It is a further object of this invention to provide a means for accomplishing this increased respiratory response which is flexible and light weight and can be worn without distracting the athlete from his training.